1. Field of the Invention
This application concerns methods for applying a material to the surface of a polymer article and to polymer articles so produced.
2. Discussion of Related Art
Typical methods used in the mass production of polymer articles are injection moulding and calendering, the latter process being frequently combined with extrusion.
Injection moulding is performed by heating a suitable polymer until molten, injecting the molten polymer into a mould, allowing the polymer to cool and harden, and removing the moulded article from the mould. This process maybe automated and therefore used to produce a rapid succession of identical articles. The mould used may have means for cooling, in order to increase the speed of hardening of the polymer. A removable shim may be incorporated into the mould, and this shim may bear surface structure and/or texture that is transferred to the polymer article during the moulding process. Alternatively, such structure may be present on the mould.
Calendering is a process used to manufacture polymer sheeting. A suitable polymer in pellet form is heated and forced through a series of heated rollers until the polymer sheet reaches the desired dimensions. The sheeting is then passed through cooling rollers in order to cool and set the polymer. Frequently, texture is applied to the polymer sheet during the process, or a strip of fabric is pressed into the back of the polymer sheet to fuse the two together.
The calendering process may be used in combination with extrusion—the extruded polymer form may be passed through the heated rollers of the calender as above until the required dimensions are obtained, and then passed over cooling rollers to set the form of the polymer.
In biotechnological applications, it is desirable to apply functional coatings to defined areas of articles for laboratory use, for example, multi-well plates, in order to reduce the likelihood of cross-contamination of samples. A method of producing such articles at low cost would be particularly desirable as many such articles must be used only once. It may be envisaged that the functional coating may be a coating to increase the affinity of defined regions of a surface for a reagent of interest, or for a biological marker or binding agent, such as an antibody or suitable fragment thereof. Alternatively, such a biological molecule may be applied directly to the polymer article as the functional coating.
Microfluidic channels, an example of a micro total analysis system, in which fluids are brought together to react and are subsequently monitored, may be mass-produced by moulding channels into a polymer surface. One method of introducing the ability to influence and monitor the state of the system is to integrate electronic circuits on the polymer surface, which may be connected to external electronics. The introduction of means for producing these integrated electronics during the process for producing the polymer channels is desirable.